1. Field
This invention relates to cryptographic systems.
2. Description of Related Art
Encrypting documents to be exchanged often requires the difficult task of keeping track of and managing encryption software and sets of encryption and decryption keys. Typically a user must first obtain a set of keys as well as complex encryption software and then know which keys to use in encrypting and decrypting information. Often a user may spend a large amount of time managing encrypting and decrypting information. A user may forget which keys to use or how to use the encryption/decryption software if the user has not used the application recently. A user may likewise lose or forget where the necessary keys are stored.
Further, the encrypted information and/or keys may be transferred on various unsecured media between processing devices or systems that may allow for interception of keys and encrypted information. This interception of the keys and/or encrypted information may lead to the unauthorized decryption of encrypted information. For public systems, authentication and certification of publicly available keys requires additional effort to prevent passive theft of data and tampering with data during transmission and storage.
Also, it may be difficult to remove authorization or permissions for particular users to decrypt encrypted information. If encrypted information is being transferred to multiple users at various processing devices and then one user should no longer be permitted access to the information, new encryption/decryption software and/or keys may have to be sent to all the other users in order to make sure that the disallowed user is not likely to obtain the information. This is typically only possible with public, two-way systems. Most document encryption sharing systems (that are not public) are one-way. Once a user has access, they generally always have access. There is generally no way to revoke a user's permission in RSA methods or other similar cryptography methods.